1. Field of the Invention
The present invention is directed toward a method for accelerating the delivery of a vasodilating agent to the penis. The method of the present invention comprises ingesting a vasodilating agent into the body at a point of ingestion external to the penis, and transmitting ultrasound energy into the penis at a sufficient frequency and intensity to increase hemodynamic activity.
2. Description of the Prior Art
Erectile dysfunctionality may result from neurogenic, vasculogenic, hormonal, and/or psychogenic causes. The term xe2x80x9cerectile dysfunctionalityxe2x80x9d, as used herein, refers to the inability or impaired ability of a male patient to experience a penile erection. The urological arts have devised a number of therapies for treating erectile dysfunctionality. These therapies include psychological, pharmacological, and electrical therapies.
A method and device for electrically stimulating a penile erection is disclosed in U.S. Pat. No. 4,585,005 to Lue et al. The method disclosed in Lue includes the implantation of an electrode on the cavernous nerves The electrodes of Lue are connected to a receiver that is subcutaneously implanted in the patient. The method and device disclosed in Lue requires surgery. Additionally, if the device disclosed in Lue malfunctions, surgery is required to remove it. Surgery is expensive and time consuming. Additionally, many patients may have emotional or psychological aversions to having electrodes implanted in their penis.
An apparatus for electrically stimulating penile tissue to cause a penile erection is disclosed in U.S. Pat. No. 5,571,118 to Boutos. Boutos discloses the use of a ring having a conductive surface that is placed on the penis and/or the scrotum. There is a risk that such a device may short circuit, if used in an electrically conductive environment, such as a hot tub. This is a major drawback of external electrical therapies, as contrasted with external ultrasound therapies. The use of ultrasound transducers on submerged patients has been applied in other nonanalogous arts, such as extracorporeal shock wave lithotripsy.
An apparatus for electrically stimulating a penile erection is disclosed in U.S. Pat. Nos. 4,542,753 and 4,663,102 to Brennan et al. Brennan discloses a body member for insertion into the rectum of a patient. The body member comprises surface mounted electrodes. Brennan teaches insertion of the body member sufficiently deep into the patient for at least one electrode to contact the prostate gland. The device disclosed by Brennan is highly invasive. Patients may experience physical discomfort from the rectal insertion of the device disclosed in Brennan.
Pharmacological therapies for erectile dysfunctionality include the injection of drugs into the penis. Such methods are disclosed in U.S. Pat. No. 5,236,904 to Gerstengerg et al. and U.S. Pat. No. 4,127,118 to Latorre. Many male patients find the thought of jabbing a hypodermic needle into their penis to be discomforting. Penile injections may also result in the buildup of scar tissue, bleeding, and persistent prolonged erection (priapism). The unacceptability of therapies requiring the intracavernosal injection of drugs into the penis is well documented in the urological arts (See U.S. Pat. No. 5,482,039 to Place et al. and U.S. Pat. No. 5,731,339 to Lowrey; and Padma-Nathan, Treatment of Men With Erectile Dysfunction With Transurethral Alprostadil, The New England Journal of Medicine, 336:1-7, Jan. 2, 1997).
Other pharmacological therapies for erectile dysfunctionality include delivering a drug directly into the urethra of a patient. Methods and devices for transurethral delivery of drugs into the penis are disclosed in U.S. Pat. Nos. 5,242,391 and 5,482,039 to Place et al. These transurethral drug delivery methods involve inserting a shaft into the urethra. The insertion of a shaft up the urethra may cause discomfort in many patients or be objectionable for many of the same reasons that penile hypodermic needle injections are objectionable.
Pharmacological agents for the treatment of erectile dysfunctionality, including vasodilators such as phosphodiesterase (PDE) inhibitors, or alpha adrenergic blockers, may also be delivered orally, transmucosally, transdermally, intranasally and/or rectally. Oral medications are available, pursuant to U.S. Food and Drug Administration (FDA) regulations, under the trademarks VIAGRA (a PDE inhibitor) from Pfizer, Inc. of New York, N.Y., and VASOMAX (an alpha adrenergic blocker) from Zonagen, Inc. of The Woodlands, Texas, or its licensees. Such oral medications are described in U.S. Pat. No. 5,731,339 to Lowrey and U.S. Pat. No. 5,565,466 to Gioco, et al.
Orally, transmucosally, transdermally, intranasally, and/or rectally ingested pharmacological agents for the treatment of erectile dysfunctionality must be dissolved into the blood stream and transported through the body to the penis. Methods of transporting such pharmacological agents to a desired site of effect, are disclosed in U.S. Pat. No. 5,565,466 and are incorporated herein, in their entirety. The time required for such pharmacological agents to be dissolved into the blood stream and transported to a site where they will relax the smooth muscle tissue in the corpora cavernosa, resulting in increased penile hemodynamic activity sufficient to cause an erection (referred to herein as the xe2x80x9ccirculatory medication response timexe2x80x9d), can be as long as one hour (see website of Zonagen, Inc). This time period can be unsatisfactory to many men and their consorts, who desire spontaneity in their sexual relations.
The present invention provides an ultrasonic therapy for hemodynamic stimulation of the penis that does not require (1) the injection of drugs into the penis, (2) surgical implantation of electrodes into the penis, or (3) the insertion of electrodes into the rectum. The method of the present invention may be used in an electrically conductive medium, such as a pool or hot tub, without the short circuiting risk present in prior art methods of electrotherapy for penile dysfunctionality. The present invention may be used to reduce the circulatory medication response time by accelerating the circulation of blood comprising a vasoactive or vasodilating agent, thereby reducing its transport time.
Blood is the hydraulic driving fluid that provides the mass increase and force which result in a penile erection. Under normal conditions, a penile erection occurs when the mass flow rate of blood into the penis exceeds the mass flow rate of blood out of the penis for a certain time interval. Vasculogenic erectile dysfunctionality may result from a restriction or blockage of blood flow into the penis or from excess blood flow out of the penis. The present invention is aimed at treating vasculogenic erectile dysfunctionality that results from inadequate blood flow into the penis. The present invention may also be used with devices intended to restrict the venous outflow of blood from the penis, such as the venous flow controller sold under the trademark ACTIS by Vivus, Inc. of Menlo Park, Calif.
The present invention provides a method for stimulating hemodynamic activity within a penis. The first method step of the present invention is coupling an ultrasound source to a penis. Genital lesions, such as warts or herpes simplex Type-2 lesions, can absorb and/or attenuate ultrasound thereby reducing the therapeutic effectiveness of the present invention. Accordingly, in a preferred embodiment, the ultrasound source is coupled to a lesion free region of the outer surface of a penis.
The second method step of the present invention is transmitting ultrasound energy into the corpora cavernosum of the penis at a sufficient frequency and intensity to increase hemodynamic flow within the penis. The frequency used is a function of the depth of desired penetration into the corpora cavernosum.
Initially, a frequency in the range of 2.5-3.5 MHz is desirable. As hemodynamic activity in the penis increases and the penis expands circumferentially, it is desirable to reduce the frequency of ultrasound energy from the initial frequency to a reduced frequency in the range of 1.8-2.5 MHz. The precise values of initial and reduced frequencies will be a function of the diameter of the penis being treated.
A portion of the ultrasound energy transmitted into the body is converted to thermal energy. The increased blood flow resulting from the use of the present invention provides a thermal transport medium for transporting and dispersing thermal energy introduced from the transmission of ultrasound energy. This thermal transport helps to minimize localized temperature increases within the penis. In a preferred embodiment, the ultrasound energy is emitted from one or more ultrasound transducers housed within a portable housing. Localized temperature increases can be further minimized by moving the portable housing relative to the penis being treated so as to disperse the transfer of thermal energy in the corpora cavernosum.
The present invention also provides a method for monitoring the effect of the stimulation therapy of the present invention. The present invention also includes ultrasonographically measuring one or more hemodynamic parameters within the penis. These hemdynamic parameters may include blood flow velocity, blood pressure, and/or blood temperature. The measured hemodynamic parameters can be graphically displayed to provide a real time indication of hemodynamic and/or thermal-hydraulic parameters within the penis. The measured hemodynamic parameters may be transmitted to a remote terminal for analysis by a remotely located health care professional. Alternatively, the measured hemodynamic parameters may be analyzed by an expert system located either remotely or with the patient.
The present invention is also directed toward an apparatus for stimulating hemodynanic activity within a penis. The apparatus of the present invention comprises an ultrasound generator, and a portable housing coupled to the ultrasound generator. The housing comprises at least one ultrasound trigger and a first transducer mounting assembly. The invention further comprises a position adjuster coupled to the first transducer mounting assembly and a second transducer mounting assembly mounted across from the first transducer mounting assembly. The second transducer mounting assembly is coupled to the position adjuster.
A first ultrasound emitter is mounted in the curved lower transducer mounting assembly. The first ultrasound emitter is connected to the ultrasound trigger and to the ultrasound generator. A second ultrasound emitter is mounted in the curved second transducer mounting assembly. The second ultrasound emitter is connected to the ultrasound trigger and to the ultrasound generator. The apparatus of the present invention may also be used to ultrasonographically measure one or more penile hemodynamic parameters.